4-(1H-1,2,4-Triazol-3-yl)-4H-1,2,4-triazole monohydrate

In the title mol­ecule, C₄H₆N₆O, the dihedral angle between the two triazole rings is 2.97 (1)°. The crystal structure is stabilized by one N—H...O, two O—H...N and three C—H...N(or O) hydrogen bonds, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](N-C) = 0.003 Å
• R factor = 0.034
• wR factor = 0.089
• Data-to-parameter ratio = 6.6

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT113_ALERT_2_A ADDSYM Suggests Possible Pseudo/New Spacegroup .       C2/c

Author Response: Although the two triazole rings are related by pseudosymmetry. We can exclude centrosymmetric structure in space group of C2/c because (i) the R values are significantly worse (R1=15 and wR2=34%), (ii) the U values are more anisotropic than in Cc (iii) the structure is disordered.

Alert level B
PLAT111_ALERT_2_B ADDSYM Detects (Pseudo) Centre of Symmetry .....        100 PerFi

Alert level C
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       6.61
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              H2 O

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.00
           From the CIF: _reflns_number_total                727
           Count of symmetry unique reflns          729
           Completeness (_total/calc)             99.73%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

   1 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Recent interest in substituted 1,2,4-triazoles has arisen in part from their transition metal complexes with intriguing structures and specific magnetic properties (Garcia et al.,1997; Kahn & Martinez,1998; Fujigaya et al.,2003). However bitriazole ligands have not been extensively exploited up to now, and herein we reported the crystal structure of (I).

In (I) (Fig.2), the two triazole ring are almost coplanar with a dihedral angle of 2.97 (1)° between them. The bond lengths and angles are unremarkable.

The crystal structure is stablized by one N–H···O, two O–H···N and three C–H···N(or O) hydrogen bonds. In detail, the water O atom O1 acts as a hydrogen bond donor, via. H1A and H1B, to the atom N5 at (-3/2 + x, 1/2 - y, -1/2 + z) and atom N6 (x, 1/2 + y, z), respectively, forming a one-dimensional chain along the [001] direction. In addition, the atom N2 at (x,y,z) acts as hydrogen bond donor, via. H2A, to the water O atom O1 in the same symmetric unit, linking adjacent chains into a three dimensional framework (Fig.3). Analysis using PLATON (Spek, 2003) shows that there are other three C–H···N(or O)(Table 2) hydrogen bonds which further stabilize the crystal structure. In addtion, π–π interactions are observed between the triazole ring N1—N3/C1/C2 at (x, y, z) and the other five-numbered ring N4—N6/C3/C4 at (-1 + x, y, z). The dihedral angle between the two triazole rings is only 2.97 (1)°, with an interplanar spacing of 3.273 (1) Å, a ring centroid separation of 3.635 (1) Å.

Related literature

There has been recent interest in substituted 1,2,4-triazoles (Fujigaya et al., 2003; Garcia et al., 1997; Kahn & Martinez, 1998).

S2. Experimental

The title compound (I) was prepared by reacting diformylhydrazine (0.046 mol, 4.0 g) and 3-amino-1,2,4-triazole 0.046 mol,3.9 g). The reactant mixture was heated slowly to 433 K for an hour. The cooled reaction mixture was dissolved in 25 ml of boiling water and filtered. On cooling, 4.4 g of the product separated. Recrystallization from hot water gave large white crystals. Elemental analysis(%) for C₄H₆N₆O, found (calculated): C 31.12 (31.13), H 3.80 (3.89), N 54.60 (54.49). IR(cm^-1,KBr):3352.21, 3119.57,2881.59, 2733.65,1789.84,1657.08,1575.38,1505.81,1371.08,1303.73, 1290.26,1142.12, 1051.33,986.29, 958.04,897.31,877.09,738.58, 629.96,563.66.

S3. Refinement

When the structure of (I) is solved and refined in the centrosymmtric space group C2/c with half a molecule in the asymmetric unit, the structure is disordered with R values that are significantly higher (R1=15 and wR2=34%) and the anistropic displacement parameters have unusual values. In the absence of significant anomalous dispersion effects Friedel pairs were merged. H atoms bonded to O1 and N1 were located from the difference maps with and refined with constraints of O–H = 0.86 (2) Å, H–H =1.35 (2) Å, N–H = 0.86 (2) Å; U_iso(H) = 1.5U_eq(O) and U_iso(H) = 1.2U_eq(N). H2, H3 and H4 were placed in calculated positions with C—H = 0.93 Å and U_iso(H) =1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON.

Figures

	Fig. 1. Reaction scheme.
	Fig. 2. Molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The dashed line indicates an intermolecular hydrogen bond.
	Fig. 3. Part of the crystal structure of (I), showing the formation of a three-dimensional network from hydrogen bonding (dashed lines).

4-(1H-1,2,4-Triazol-3-yl)-4H-1,2,4-triazole monohydrate

Crystal data

C4H4N6·H2O	F(000) = 320
Mr = 154.15	Dx = 1.538 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 1837 reflections
a = 3.8716 (3) Å	θ = 2.6–28.1°
b = 15.8019 (14) Å	µ = 0.12 mm^−1
c = 10.8874 (9) Å	T = 296 K
β = 91.785 (1)°	Plate, colorless
V = 665.75 (10) Å^3	0.20 × 0.10 × 0.04 mm
Z = 4

Data collection

Bruker SMART APEX CCD area-detector diffractometer	727 independent reflections
Radiation source: fine focus sealed Siemens Mo tube	709 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
0.3° wide ω exposures scans	θmax = 27.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −4→4
Tmin = 0.976, Tmax = 0.988	k = −18→20
2254 measured reflections	l = −13→13

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.089	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0579P)^2 + 0.1815P] where P = (Fo^2 + 2Fc^2)/3
727 reflections	(Δ/σ)max < 0.001
110 parameters	Δρmax = 0.17 e Å^−3
6 restraints	Δρmin = −0.21 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.1950 (6)	0.28332 (13)	0.7395 (2)	0.0286 (5)
C2	−0.0527 (8)	0.39041 (17)	0.7999 (2)	0.0403 (6)
H2	−0.1431	0.4331	0.8481	0.048*
C3	0.4923 (7)	0.16139 (17)	0.6439 (2)	0.0383 (6)
H3	0.4433	0.1745	0.5619	0.046*
C4	0.5157 (8)	0.16590 (16)	0.8413 (2)	0.0363 (6)
H4	0.4867	0.1829	0.9222	0.044*
N1	0.0761 (6)	0.31653 (13)	0.63646 (19)	0.0363 (5)
N2	−0.0840 (6)	0.38719 (14)	0.67866 (19)	0.0378 (5)
H2A	−0.187 (8)	0.4237 (18)	0.627 (3)	0.052 (9)*
N3	0.1248 (7)	0.32463 (13)	0.84350 (19)	0.0385 (6)
N4	0.3879 (5)	0.20801 (11)	0.74086 (18)	0.0293 (4)
N5	0.6829 (6)	0.09913 (14)	0.80910 (18)	0.0406 (6)
N6	0.6694 (7)	0.09619 (14)	0.6813 (2)	0.0412 (5)
O1	−0.4451 (6)	0.48966 (11)	0.5130 (2)	0.0423 (5)
H1A	−0.584 (9)	0.465 (2)	0.466 (3)	0.064*
H1B	−0.561 (9)	0.5245 (19)	0.553 (3)	0.064*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0330 (12)	0.0295 (9)	0.0236 (9)	−0.0055 (8)	0.0036 (8)	0.0001 (8)
C2	0.0498 (16)	0.0358 (12)	0.0356 (13)	0.0012 (10)	0.0075 (11)	−0.0059 (10)
C3	0.0481 (16)	0.0390 (12)	0.0278 (11)	0.0028 (10)	0.0025 (11)	−0.0035 (9)
C4	0.0460 (14)	0.0405 (12)	0.0224 (10)	−0.0007 (10)	−0.0013 (10)	0.0025 (9)
N1	0.0455 (13)	0.0365 (11)	0.0268 (9)	0.0037 (8)	0.0011 (8)	0.0003 (7)
N2	0.0440 (13)	0.0332 (10)	0.0363 (10)	0.0019 (8)	0.0039 (9)	0.0028 (8)
N3	0.0513 (14)	0.0393 (11)	0.0251 (9)	0.0028 (9)	0.0041 (9)	−0.0040 (7)
N4	0.0346 (11)	0.0325 (9)	0.0208 (7)	−0.0021 (7)	0.0011 (7)	−0.0002 (7)
N5	0.0477 (15)	0.0401 (12)	0.0336 (11)	0.0011 (9)	−0.0034 (9)	0.0049 (8)
N6	0.0472 (14)	0.0390 (12)	0.0373 (11)	0.0036 (10)	0.0030 (10)	−0.0022 (9)
O1	0.0460 (10)	0.0415 (10)	0.0393 (11)	0.0033 (9)	−0.0030 (8)	−0.0040 (7)

Geometric parameters (Å, º)

C1—N1	1.309 (3)	C4—N5	1.292 (4)
C1—N3	1.342 (3)	C4—N4	1.360 (3)
C1—N4	1.405 (3)	C4—H4	0.9300
C2—N2	1.323 (3)	N1—N2	1.364 (3)
C2—N3	1.326 (4)	N2—O1	2.770 (3)
C2—H2	0.9300	N2—H2A	0.895 (18)
C3—N6	1.296 (4)	N5—N6	1.392 (3)
C3—N4	1.359 (3)	O1—H1A	0.835 (18)
C3—H3	0.9300	O1—H1B	0.840 (19)
N1—C1—N3	116.9 (2)	C2—N2—O1	131.0 (2)
N1—C1—N4	121.40 (19)	N1—N2—O1	119.00 (16)
N3—C1—N4	121.67 (19)	C2—N2—H2A	129 (2)
N2—C2—N3	111.0 (3)	N1—N2—H2A	121 (2)
N2—C2—H2	124.5	C2—N3—C1	101.3 (2)
N3—C2—H2	124.5	C3—N4—C4	104.5 (2)
N6—C3—N4	110.7 (2)	C3—N4—C1	128.46 (19)
N6—C3—H3	124.6	C4—N4—C1	127.06 (19)
N4—C3—H3	124.6	C4—N5—N6	107.2 (2)
N5—C4—N4	110.7 (2)	C3—N6—N5	106.9 (2)
N5—C4—H4	124.6	N2—O1—H1A	115 (3)
N4—C4—H4	124.6	N2—O1—H1B	108 (3)
C1—N1—N2	101.0 (2)	H1A—O1—H1B	107 (3)
C2—N2—N1	109.8 (2)
N3—C1—N1—N2	0.8 (3)	N6—C3—N4—C1	179.3 (2)
N4—C1—N1—N2	−179.09 (19)	N5—C4—N4—C3	−0.2 (3)
N3—C2—N2—N1	0.3 (3)	N5—C4—N4—C1	−179.5 (2)
N3—C2—N2—O1	175.2 (2)	N1—C1—N4—C3	3.1 (3)
C1—N1—N2—C2	−0.6 (3)	N3—C1—N4—C3	−176.8 (3)
C1—N1—N2—O1	−176.24 (17)	N1—C1—N4—C4	−177.7 (3)
N2—C2—N3—C1	0.2 (3)	N3—C1—N4—C4	2.4 (3)
N1—C1—N3—C2	−0.6 (3)	N4—C4—N5—N6	0.3 (3)
N4—C1—N3—C2	179.2 (2)	N4—C3—N6—N5	0.2 (3)
N6—C3—N4—C4	0.0 (3)	C4—N5—N6—C3	−0.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···N5^i	0.84 (2)	2.15 (2)	2.962 (3)	163 (4)
O1—H1B···N6^ii	0.84 (2)	2.10 (2)	2.930 (3)	169 (4)
C2—H2···O1^iii	0.93	2.49	3.392 (3)	163
C3—H3···N3^iv	0.93	2.50	3.334 (3)	149
C4—H4···N1^v	0.93	2.35	3.226 (3)	157
N2—H2A···O1	0.90 (2)	1.88 (2)	2.770 (3)	173 (3)

Symmetry codes: (i) x−3/2, −y+1/2, z−1/2; (ii) x−3/2, y+1/2, z; (iii) x, −y+1, z+1/2; (iv) x+1/2, −y+1/2, z−1/2; (v) x+1/2, −y+1/2, z+1/2.